At 4:53 p.m. local time on January 12, 2010, a 7.0-magnitude earthquake struck Hispaniola Island, just 15 kilometers (10 miles) southwest of the Haitian capital of Port-au-Prince. Besides its strong magnitude, the earthquake’s shallow depth of roughly 8.3 kilometers (5.2 miles) ensured that the densely populated capital suffered violent shaking.

This map shows the topography and tectonic influences in the region of the earthquake. Lighter colors indicate higher elevation. Black circles mark earthquake locations determined by the U.S. Geological Survey, and circle sizes correspond with quake magnitudes. Dozens of aftershocks followed the main quake. Red lines indicate fault lines.

The epicenter of the quake appears just south of the Enriquillo-Plaintain Garden Fault, the southernmost of two major east-west-trending faults that bear the stress of the convergence of the Caribbean and North America tectonic plates in this location. Though faults are weak spots or fractures in the Earth’s crust below the surface, very often there are topographical clues to their presence. In this case, the presence of the fault is indicated by long, straight valley cutting through southern Haiti, just south of Port-Au-Prince. The Enriquillo-Plaintain Garden Fault is a strike-slip type fault, with the Caribbean plate moving eastward with respect to the North America plate.

NASA Earth Observatory image by Jesse Allen, using earthquake and plate tectonics data from the USGS Earthquake Hazard Program, elevation data from the Shuttle Radar Topography Mission (SRTM) courtesy of the University of Maryland’s Global Land Cover Facility. Caption by Michon Scott and Rebecca Lindsey.